Summary This article is the second part* of a review of the application of mathematical models of the transmission dynamics of infectious disease in the design of community-wide immunization programmes. We illustrate the use of models in predicting the potential impact of different vaccination strategies for a variety of viral infections with emphasis on the design of optimal policies for mass vaccination. Details of the structure and assumptions of the mathematical models, and the underlying epidemiological concepts upon which they are based, were the subject of the first part of the review.1 Case studies are used to illustrate the application of mathematical models to three issues of recent concern, namely: (i) the debate over the control of congenital rubella infection, (ii) the merits and possible hazards of mass vaccination against varicella-zoster, and (iii) whether or not it is always in the interests of the community to adopt a vaccine with the lowest complication rate. These illustrate the broad range of issues to which models may be applied and the topicality of the modelling approach to immunization policy design. Finally, we indicate future applications of mathematical models to other important issues facing public health authorities.